Conventionally, illumination devices of high-frequency heating devices with a range hood are equipped with a lower illumination lamp which is attached to the bottom surface of the heating device main body and a heating chamber illumination lamp (chamber lamp) which is disposed inside the heating device main body (refer to Patent Document 1, for example).
Lower illumination lamps are required to have a function of illuminating a gas or electric heat-cooking device installed under the high-frequency heating device and what is being cooked by the heat-cooking device. Therefore, lower illumination lamps are required to provide sufficient illuminance to enable judgment of the degree of cooking of what is being cooked by a gas cooker below. Furthermore, customers (users) require lower illumination lamps to also function as kitchen illumination lamps (indirect illumination). Lower illumination lamps are used at a much higher frequency for much longer time than heating chamber illumination lamps which are used as chamber lamps.
Furthermore, attached to the bottom surface of the main body of the high-frequency heating device, lower illumination lamps tend to be affected by a high temperature of gas that is generated by a gas or electric heat-cooking device installed under the high-frequency heating device. Still further, illumination devices including lower illumination lamps are required to exhibit high insulation performance for the voltage of a home commercial power source even in a high-temperature, high-humidity environment.    Patent Document 1: JP-A-2003-28431